7. Muhammad Ali

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A three-time World Heavyweight Champion known as much for his boxing dominance as his self-aggrandizing persona (which was, in fact, a public image constructed on the advice of pro wrestler "Gorgeous George" Wagner), Ali won a gold medal in the 1960 Olympics, then beat 7-to-1 favorite Sonny Liston for his championship in '64. Boxing was soon overshadowed by the social issues of the decade — Ali declared himself a conscientious objector to the Vietnam War, and was arrested, convicted of draft evasion and stripped of his title in 1967.